Jonas Holm

Senior Associate, Member of the Finnish Bar, M.Sc. (Econ.)

Services

  1. Environment, Energy & Green Transition

Contact details

I advise clients on energy law matters, industrial and infrastructure projects, and contractual issues related to these sectors.

A key part of my work is an interdisciplinary approach and understanding the diverse forces that shape the landscape in which companies operate. Businesses that understand the regulatory, political, economic and commercial realities of an increasingly interconnected world gain a competitive advantage. I provide holistic and strategic legal advice that goes beyond regulatory considerations by incorporating interdisciplinary and commercial insights.

I am currently pursuing doctoral studies in energy law. In addition to my law degree, I hold a Master’s degree in economics, which enables me to bridge legal analysis with commercial strategy.

Before joining Castrén & Snellman, I advised both Finnish and international industrial companies, as well as private equity sponsors, at another leading law firm. My experience spans complex transactions and regulatory frameworks, always with a focus on delivering pragmatic, business-oriented solutions. This multidisciplinary foundation allows me to provide specific advice to diverse stakeholders and to help our clients build sustainable success stories.

Latest references

Delta Capacity – Project financing of two battery energy storage systems (BESS)
We advised Delta Capacity AG in a project financing of two battery energy storage systems (BESS). The financed projects are among the largest BESS developments in Finland to enter construction with 250 MW / 600 MWh combined capacity. The financing was provided by Société Générale with support from Finnvera. Construction of both projects, located in Lapinlahti and Teuva, has already begun and the commercial operations are targeted to commence in late 2027 with partial tolling agreements already in place for both assets. The project in Lapinlahti is executed in partnership with Covenergo, while the project in Teuva is executed in partnership with Strioga Family Foundation. Delta Capacity is a Swiss developer of utility-scale battery storage systems. The projects strengthen Delta Capacity’s growing Nordic portfolio and support the flexibility of Finland’s electricity system by adding energy storage capacity, enabling production optimization as well as participation in electricity markets and reserve services.
Case published 28.10.2026
Delta Capacity – Acquisition of BESS Project
We acted as Finnish legal advisor to Delta Capacity in connection with its acquisition of the ready-to-build Karppio battery energy storage system (BESS) project from Helios Nordic Energy. The acquisition was made and the project will be implemented together with Strioga Family Foundation. The Karppio BESS project is located in Teuva, Finland, and has a capacity of 125 MW / 300 MWh. Delta Capacity will lead the remaining development of the project through to commissioning, planned for 2027, and will serve as long-term asset manager. Delta Capacity is a Swiss-based developer of utility scale battery storage systems. The acquisition adds to Delta Capacity’s growing Nordic portfolio. 
Case published 20.7.2026
Oomi Solar – Sale of a Solar Power Plant and Battery Energy Storage Project
We advised Oomi Solar Oy on the sale of a solar power park and battery energy storage project to Tuulipolar Oy. The transaction concerned a 24 MWp solar power plant and a 36 MW / 70 MWh battery energy storage system (BESS) to be constructed in Tornio. Tuulipolar Oy will act as the owner and operator of the plant, while Oomi Solar Oy will be responsible for its design and construction. The project will form the world’s northernmost industrial hybrid power plant, contributing to Finland’s green energy transition by increasing renewable energy production and electricity storage capacity in Northern Finland. The hybrid solution enables optimization of production as well as active participation in electricity markets and reserve services, improving the project’s profitability and supporting the balance of the electricity system year-round. Electricity production from the hybrid plant is expected to begin in 2028. Oomi Solar Oy is a Finnish renewable energy expert with experience from nearly 200 MW of installed solar capacity. The company helps businesses and communities accelerate the green transition by offering comprehensive solutions, including solar power plants, energy storage systems, and related lifecycle services from project development to maintenance. Oomi Solar Oy employs more than 20 energy professionals and delivers solar power projects across Finland. The company’s vision is to be Finland’s most desired partner for solar energy and energy solutions.
Case published 5.6.2026
Nscale – Data centre project
Castrén & Snellman advised Nscale, a European AI infrastructure company, in connection with its planned data centre project in Harjavalta, Finland. The facility will be located in the Sievari industrial area. Castrén & Snellman’s advisory role encompassed the negotiation and execution of a site securing and development agreement (SSDA) with Fortum, as well as the preliminary land sale process for the Sievari site with the Town of Harjavalta. Under the SSDA, Fortum supports the advancement of Nscale’s project development, including grid connection design and permitting.
Case published 15.4.2026
Downing – Acquisition of the entire share capital of Tornionlaakson Voima
We advised UK-based investment company Downing in its acquisition of the entire share capital of Tornionlaakson Voima Oy. Tornionlaakson Voima owns three hydropower plants in the Tengeliönjoki river system – the Portimokoski power plants in Ylitornio, the Jolmankoski power plants in Raanujärvi and the Kaaranneskoski power plants in Sirkkakoski. The power plants produce a total of approx. 45 gigawatt-hours of electricity per year. Tornionlaakson Voima’s daily operations will continue normally, and the transaction will not affect customers. The consummation of the transaction is subject to the approval of the Ministry of Economic Affairs and Employment. Downing has over 35 years’ experience in providing a wide range of investment solutions to the needs of institutional investors, advisers and retail investors. The company manages over £2 billion in assets in both the private and public markets and its current hydro power portfolio includes approx. 50 hydro power plants in the Nordics. 
Case published 27.3.2026
Brookfield – EUR 1 billion holdco financing for DayOne Data Centers
We advised a leading global investment firm Brookfield, alongside a global sovereign wealth investor, on the Finnish law aspects of a EUR 1 billion holdco financing for DayOne Data Centers, a Singapore-headquartered developer and operator of hyperscale data centres. Structured as a seven-year secured holdco financing facility of €500 million, expandable to €1 billion – and secured by DayOne’s Finland platform – the financing will support the rollout of hyperscale developments in Lahti and Kouvola, providing nearly 300MW of planned capacity across Finland. The proceeds will also support DayOne’s global expansion across the EU and APAC, with flexibility to allocate to other key growth markets as required.
Case published 29.1.2026
Martela Corporation – Directed share issue and combination of share series
We acted as legal adviser to Martela Corporation in its directed share issue, through which Martela raised gross proceeds of approximately EUR 7.2 million to strengthen the company’s financial position and liquidity and to create headroom for continuing the necessary development and efficiency measures. In connection with the directed share issue, Martela’s unlisted series K shares, which carried greater voting rights, were combined with its listed series A shares. Following the combination, the company has only one share series, which is traded on the regulated market maintained by Nasdaq Helsinki Ltd, with each share carrying one vote and otherwise identical rights. Martela is a Nordic leader specialising in user-centric working and learning environments. With over 80 years of experience, Martela creates the best places to work and offers its customers the Martela Lifecycle solutions which combine furniture and related services into a seamless whole.
Case published 27.10.2026
Banyan Software – Acquisition of Carus Ferry
We acted as legal adviser to Banyan Software on its acquisition of Carus Ferry, a Finland-based provider of reservation, check-in and port operations software for ferry and passenger shipping operators. The acquisition further strengthens Banyan Software’s presence in the Nordic region while providing Carus with a long-term partner to support its continued growth and development. Carus was founded in 1998 and is headquartered in Mariehamn on the Åland Islands, Finland. The company develops mission-critical software for ferry, cruise and passenger shipping operators, covering the full passenger journey from booking and ticketing to capacity management, check-in and boarding. Carus also provides port automation, onboard sales systems and business information tools. The company serves approximately 30 operators across four continents and is the largest vendor by customer count in ferry reservation and departure control. Banyan Software is an acquirer and long-term operator of mission-critical software businesses serving specialised industries. Founded in 2016, Banyan follows a buy-and-hold-for-life approach and supports the long-term growth and development of its portfolio companies. Banyan operates more than 130 portfolio companies across North and South America, the United Kingdom, Europe and APAC. Following the acquisition of Carus, Banyan operates three businesses in the Nordic region.
Case published 20.10.2026

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